Within the scope of the present invention, an intraluminal implant is understood to mean prostheses which are introduced into hollow organs of the body, where they remain or disintegrate or break down (degrade) after a predefined period of time. Intraluminal implants of this type are introduced by means of a catheter into the respective hollow organ. Intraluminal implants generally substantially have the shape of a tube and have a lattice structure, which corresponds to the dimension of the hollow organ into which the implants are introduced. Intraluminal implants that carry artificial heart valves are likewise known. An artificial heart valve of this type consists substantially of a flap formed of mostly biological tissue, which is secured in a lattice structure which carries the artificial heart valve. Artificial heart valves of this type can likewise be implanted by means of catheters at the location of the natural heart valve.
The present invention will be described hereinafter on the basis of the example of an artificial heart valve with a lattice structure (hereinafter: heart valve prosthesis), as is implanted at the location of the natural heart valve. The present invention is not limited however to this application, but is generally suitable for fitting intraluminal implants of the type described in the introduction to a catheter shaft.
A heart valve prosthesis of this type is implanted via a catheter. Here, the catheter is introduced for example via the artery in the groin, and the heart valve prosthesis is brought by means of the catheter to the site of implantation. There, the heart valve prosthesis unfolds and anchors in the vessel at the position of the natural heart valve. The natural heart valve is not removed here, but is merely displaced by the heart valve prosthesis.
For insertion by means of a catheter, the heart valve prosthesis has to be fitted appropriately to the shaft of the catheter for insertion of the heart valve prosthesis. Here, the diameter of the heart valve prosthesis has to be much smaller for insertion than at the site of implantation. The heart valve prosthesis is accordingly compressed (“crimped”) onto the catheter shaft and is expanded at the site of implantation after insertion. Here, the expansion can occur in a self-expanding manner, as is the case with a stent, or by expansion of a balloon.
A method and a device for fitting a stent to a catheter shaft are described in U.S. Pat. No. 6,387,117. In accordance with the prior art described there, the stent is brought over the catheter shaft and is crimped by means of a press onto the catheter shaft. The press has at least two press dies, between which the catheter shaft with the stent is introduced. The press dies consist of a multiplicity of plates that have conical recesses and are arranged in parallel. The plates of the two dies are arranged here in an offset manner. The stent is accordingly pressed onto a catheter shaft by the adjacent conical recesses.
When fitting a heart valve prosthesis to a catheter shaft by a method according to the prior art, there is the risk that the heart valves consisting of biological tissue will tilt or bend. This would cause damage to the valves and would lead to a resultant malfunctioning, which is to be avoided at all costs.